90 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



there is a cluster, relatively simple in character, which is 

 perhaps part of the previous complex, and may be called 

 "awareness"; this is also capable of affecting objects, since 

 when it is absent objects disappear completely. This is the 

 direct acquaintance whose essentiality in knowledge was 

 demonstrated in Chapter III. 



These types of object unite into perception in a way which 

 may be symbolized asA— M — B— P — 0. represents 

 something which may be called the end-object; it is that 

 which is presumed in any perceptual act to be the ultimate 

 thing known at the moment, i.e., the content of the aware- 

 ness. Attention has already been called to the fact that all 

 knowledge demands a situation of the kind described by 

 saying, 'I am now aware of such-and-such." The. end- 

 object is the final "such-and-such" of perception, i.e., it is 

 that element of the perceptual act which cannot in the given 

 situation be considered as a tool or instrument of percep- 

 tion, and hence as a part of the awareness rather than of the 

 content. An end-object is that which one perceives, not 

 that by means of which something is perceived. P repre- 

 sents that complex of elements which constitute the physical 

 medium in which is found. This includes its spatial and 

 temporal location, its illumination, the atmosphere or other 

 gas surrounding it, and so on; it also includes any instru- 

 ments placed in that medium for the purpose of recording, 

 measuring, magnifying, analyzing, intensifying, and other- 

 wise conveying information, through physical stimuli, of 

 the character of the end-object. Objects which function 

 as physical media may also function as end-objects, though 

 not usually in the same situation; for example, one may 

 make a physical study of a thermometer. But if a ther- 

 mometer is end-object of an act of perception, it is not 

 ordinarily at the same time a medium for conveying informa- 

 tion about some other event. An end-object indicates, at 

 the moment, nothing beyond itself; a medium is always a 

 vehicle. B represents that complex of elements which con- 

 stitute the body of the perceiver, i.e., the nervous medium 



